This invention relates to the field of devices used to transplant trees and other large plants with minimal disruption to the root ball, specifically to a flat-bottomed container having side walls with an arcuate configuration for optimizing root ball development when used as a growth container prior to transplant, and at least one sturdy ring on its outside surface that is configured for lifting the combined weight of the container, plant, and root ball, which for very large plants and containers will be well in excess of one hundred pounds. When more than one ring is present, although not critical and not limited thereto, the rings can be horizontally distanced from a next adjacent ring, positioned vertically above or below another ring, and/or placed at uniformly spaced-apart positions about the container's outside surface. One application of the present invention is for a large plant or tree to be grown in the present invention container until a desired transplant size is achieved, where its arcuate side walls provide an optimized non-restrictive root growing area. The combined tree and container are then transported by truck or other transport device such as a trailer to its intended transplanting location in the container. Thereafter, the present invention container and its associated tree or plant are moved to a pre-dug hole at the transplanting location using one or more of its sturdy rings and the assistance of a forklift connected thereto, or other machine capable of lifting and moving the combined weight of the container, plant, and root ball. Then, once the forklift or other lifting equipment through use of its ring connection to the present invention container positions it over the pre-dug hole and rotates its raised side into a more perpendicular orientation relative to the ground surface below, gravity will cause the root ball to slide out of the container and into the pre-dug hole. Optionally, the upper edge of the container can be used to catch the lip of the pre-dug hole for assistance in vertically rotating the present invention container and thereafter centering the root ball within the pre-dug hole. Another application of present invention containers is use at construction sites for preserving large plants and mature trees, and moving them to new locations and/or temporarily housing the trees and plants until they can be replaced in their original positions. By protecting the root balls of such permanently or temporarily relocated trees and plants, and helping the root balls to remain intact during transport, the present invention containers enhance the opportunity for transplant success. Typically, the present invention containers have a diameter dimension of approximately four feet or more, with the minimum contemplated diameter being approximately one-and-one-half feet. Optionally, the container also may have one or more drainage holes near to or through its bottom surface, as well as anchoring means that assist in maintaining the plant and container in an upright position in the presence of strong winds, although the curved configuration of the container's outside surface provides some self-righting assistance to the container and plant therein even when no anchoring means is present. Such anchoring means can include, but is not limited to, one or more anchoring passages through which a stake may be driven at an angle into the ground supporting the container.